Heat exchanger plate and such a plate with a gasket

ABSTRACT

A heat exchanger plate includes a gasket groove that extends through a portion of the plate proximate to the periphery of the plate. The groove includes spaced expanded portions disposed to receive a plurality of coupling elements formed on an associated gasket. The expanded portions include tongue-like ridged portions with openings substantially perpendicular to the longitudinal direction of the gasket groove that are configured to receive the gasket coupling elements.

The invention relates to a plate for a plate-type heat exchanger.

Plate-type heat exchangers are constructed of a number of platesseparated by gaskets. In general, each plate has a rectangularconfiguration and at each corner it is provided with inlet and outletopenings for two heat exchanger media. The plate is ridged into acorrugated pattern and provided with a gasket that will, when theplate-type heat exchanger is assembled, abut on the next plate in thestack. The gasket defines a flow area that is in contact with two of thecorner openings and therefore allows flow of a first heat exchangermedium to this side of the plate. The two remaining corner openings arecut off by the gasket. The subsequent heat, exchanger plate in the stackhas been rotated 180°, and thus its gasket defines a flow area that isin contact with the two other corner openings on the opposite side ofthe first plate and permits flow of another heat exchanger medium onthis side of the plate. By rotating every other heat exchanger plate180° a plate-type heat exchanger is constructed wherein every otherspace is flushed by the first heat exchanger medium whereas theremaining spaces are flushed by tile other heat exchanger medium.

Generally, every heat exchanger plate is provided with a gasket groovewherein a gasket that is preferably made of rubber can be arranged. Inorder to facilitate assembly of the plate-type heat exchanger, thegasket is secured in the gasket groove and this can be accomplished in avariety of ways. Conventionally the gasket is glued into the gasketgroove, but in view of the fact that this causes a problem in connectionwith a subsequent disassembly of the plate-type heat exchanger,alternative mechanical attachment methods have been developed.

Such mechanical attachment methods can be divided into two groups. Inthe first group the attachment is accomplished in that the gasket isprovided with a protruding portion that can engage with an openingprovided in connection with the gasket groove. The opening can be apunched opening (eg as shown in U.S. Pat. No. 4,377,204) or it may beformed by cutting and ridging of plate material whereby an opening isformed without removal of material (eg as shown in U.S. Pat. No.4,905,758). In the other group the gasket and the gasket groove areconfigured such that the gasket extends beyond the edge of the heatexchanger plate and is secured there by means of flaps that seize aroundthe edge (eg as shown in EP 0 762 071).

The present invention relates to the group of attachment methods whereinopenings are provided by cutting and ridging of plate material as shownin U.S. Pat. No. 4,905,758, This method presents a number of advantagescompared to the other methods mentioned.

The method in which an opening is punched into the heat exchanger platenear the gasket groove is associated with the drawback that the punchingof the opening—or in reality the many holes that are spaced apart alongthe gasket groove—presupposes either a separate series of operationfollowing ridging of the plate, or it presupposes that the ridging toolis also provided with punching tools which significantly increases thecost of such tool. Besides, the latter solution is undesirable sincethere will be a risk that punched-out parts remain in the ridging tooland is thereby detrimental to the subsequent ridging/punching process.

Cutting and ridging of material to form the opening can be accomplishedin the same operation procedure as the ridging of the plate itself, andthus no separate operation procedure is required and, likewise, thedemands to the large tolerances of the cutting tool are not high, and itcan therefore relatively inexpensively be incorporated in the ridgingtool.

In the methods where the gasket and the gasket groove are configuredsuch that the gasket extends beyond the periphery of the heat exchangerplate and is secured there by means of flaps that engage around theedge, a complex configuration of the gasket is necessary which, on theone hand, increases the cost of manufacture of such gasket and, on theother, renders the mounting of the gasket cumbersome and time-consuming.

A gasket for mounting in openings formed by cutting and ridging ofmaterial may have a simple configuration and is comparatively readilymounted in the gasket groove.

U.S. Pat. No. 4,905,758 teaches a heat exchanger plate with a gasketgroove provided, at intervals, with an expanded portion that is situatedin the same plane as the gasket groove itself, and which is thereforepressed down relative to the surrounding gasket material. By thepressing-down the ends of the expanded portion have been cut open,whereby openings are formed there in a plane located substantiallyperpendicular to the longitudinal direction of the gasket groove.

The gasket is provided with protruding coupling elements that fit intothe expanded portions of the gasket groove, their configuration beingsuch that they are able to engage with the openings that are provided ateach end of the expanded portions.

Securing of the gasket is accomplished in that the ends of the expandedcoupling element of the gasket are pressed into the openings, whichmeans that the holding force is determined by the engagement between theexpanded portion of the gasket and primarily the upper edge 1 of theopenings.

It has been found that in the manufacture of heat exchanger plates witha configuration that corresponds to the one shown in U.S. Pat. No.4,905,759, it is difficult to observe the requisite tolerances on thedistance between the two upper edges of the openings, the plate materialcontracting when the initially plane plate is pressed upwards to thedesired profiled shape. The extent of the contraction depends in part onthe ridging of the surrounding material, in part on the plate materialand in part on the plate thickness. The distance between the two upperedges can thus vary from plate to plate and from coupling site tocoupling site along the gasket groove, with an ensuing undesirablevariation in the holding force between the expanded portion of thegasket groove and the coupling element of the gasket such irregularholding force may give rise to problems during assembly of a plate-typeheat exchanger since a gasket may unintentionally be displaced out ofthe gasket groove in case it is not sufficiently attached.

It is the object of the present invention to provide a heat exchangerplate of the above-mentioned type, wherein the distance between theedges with which the gasket engages can be manufactured within narrowtolerances so as to overcome the above-mentioned drawbacks.

This is obtained by configuring the plate mentioned above as featured inthe characterising part of claim 1.

Hereby a heat exchanger plate is obtained wherein the expanded portionfeatures securing openings to each side of the ridged, tongue-likeportion(s), and the distance between the openings formed can be keptwithin narrow tolerances, the ridged, tongue-like portion(s) not beinginfluenced by the contraction pattern of the surrounding material assuch during manufacture of the plate. Such configuration of the heatexchanger plate thus enables that all the mutually spaced expandedportions feature securing openings, whose mutual distance is kept withinthe same narrow tolerances independently of the ridging as such and ofthe plate material and thickness. Besides, this also means that the sameridging tool can be used in the manufacture of heat exchanger platesmade of different materials and having different thicknesses. Since thecoupling elements of the gasket that are configured for engaging withthese tolerances can also be manufactured within narrow tolerances, itis possible to obtain a homogenous holding force throughout the spacebetween the plate and the gasket.

According to a first embodiment of the invention, one ridged,tongue-like portion is provided centrally in the expanded portion, andthe coupling element of the gasket comprises two protruding parts thatare configured to engage with the openings provided at each side of thetongue-like portion. This embodiment constitutes the simplestconfiguration of a heat exchanger plate in accordance with theinvention.

According to an alternative embodiment of the invention two ridged,tongue-like portions are provided at a distance from each other in theexpanded portion. In this embodiment there is provided four attachmentopenings, viz one on each side of the two tongue-like portions.Therefore the coupling element of the gasket can be manufactured in avariety of ways, as it may be configured with protruding flaps thatengage with different openings. Thus, the coupling element of the gasketmay comprise a protruding flap configured to engage with the two middleand mutually facing openings provided at each their tongue-like portion,or it may comprise two protruding flaps that are configured for engagingwith the two mutually most distant openings provided at each theirtongue-like portion. Thus the gasket can be configured with anengagement flap that is clamped between the tongue-like portions or withengagement flaps that clamp around the two tongue-like portions.

The flaps on the couplings elements of the gasket can be configured suchthat they extend partially into the openings, or they can be configuredsuch that they press on the openings without extending considerablythere into, depending on how much holding force is desired.

Finally the coupling element of the gasket can be provided with apressure element arranged above the coupling element as such, saidpressure element not interfering with the functionality of the couplingelement of the gasket, but facilitating the mounting of the gasket onthe plate.

The invention will now be explained in further detail with reference tothe drawing, wherein

FIG. 1 shows a heat exchanger plate according to the invention providedwith a gasket;

FIG. 2 is an enlarged view of a section of the embodiment of a heatexchanger plate according to a first embodiment of the invention;

FIG. 3 shows a part of a gasket that can be mounted in the heatexchanger plate shown in FIG. 2;

FIG. 4 shows the gasket shown in FIG. 3 mounted in the heat exchangerplate shown in FIG. 2;

FIG. 5 is an enlarged view of a section of the embodiment of a heatexchanger plate according to an alternative embodiment of the invention;and

FIGS. 6–8 show parts of a gasket that can be mounted in the heatexchanger plate shown in FIG. 5.

FIG. 1 shows a rectangular heat exchanger plate 1 with corner openings 2for the heat exchanger media. The plate 1 is provided with a gasket 3that defines a flow area 4 for the one heat exchanger medium, it beingin communication with two of the corner openings 2. The remaining twocorner openings 2 are cut off by the gasket 3. Preferably the plate 1 isconfigured with a corrugated surface as shown since, on the one hand, itincreases the heat exchange across the plate 1 and, on the other,imparts rigidity to the plate 1. The corrugations are accomplished byridging in a pressing tool. When a heat exchanger is assembled everyother plate 1 with gasket 3 is rotated 180° such that the one heatexchanger medium flows between every other plate, whereas the otherflows between the remaining plates. This is a completely conventionalconstruction of a heat exchanger.

In order to facilitate mounting of the plate-type heat exchanger, thegasket 3 is attached to the plate 1. To this end, the gasket 3 isprovided with expanded portions 5 evenly distributed around the gasket.The plate 1 is configured with cut-outs that are complementary with theexpanded portions of the gasket 3 whereby the gasket 3 can be secured bymeans of these cut-outs in the plate 1.

FIG. 2 is an enlarged-scale view of a portion of the heat exchangerplate 1 according to a first embodiment of the invention.

As will appear the plate 1 is provided with a gasket groove 6 forreceiving a gasket 3. The gasket groove 6 is provided with mutuallyspaced expanded portions 7 that are complementary with correspondingexpanded portions on the gasket 3. Centrally in the expanded portion 7,an opening 8 is provided that is accomplished by the ridging of theplate 1. In this pressing operation the corrugated surface of the plate1 and the gasket groove 6 with the expanded portion 7 are provided.Simultaneously the opening 8 is formed, the two parts of the pressingtool pressing a tongue-like portion 9 upwards in relation to the gasketgroove 6 and the expanded portion 7. In the operation, two slits are cutin the plate 1, but no material is removed.

The opening 8 co-operates with a corresponding opening at the oppositeside of the tongue 9 to form the coupling means of the plate 1 for agasket, wherein the upper edge of the opening 8 will, followinginterconnecting, retain an engaging part on the expanded portion of agasket as will be described below. The width of the tongue 9 iswell-defined, and the plate material of which it consists is essentiallynot exposed to further tensions or contractions by the ridging whichmeans that the distance between the upper edges of the two engagingopenings 8 is accurately determined within narrow tolerances.

FIG. 3 shows a part of a gasket 3 that matches the gasket groove 6 inthe sheet 1 shown in FIG. 2. At intervals, the gasket 3 is provided withcoupling elements 10 that consist—in the embodiment shown—of twoprotruding flaps 11. The configuration of the gasket 3 and theprotruding tongues 11 corresponds with a high degree of accuracy to theconfiguration of the gasket groove 6 and the expanded portion 7 thereof.The flaps 11 are configured such that the parts thereof that face eachother are able to snap-lockingly engage with the openings 8 in the plate1.

Preferably the gasket is made of rubber, but it may also be made ofother material. On its top and bottom faces, the gasket 3 can also beprovided with sealing lips 12 as shown to accomplish improved sealingbetween the heat exchanger plates when assembled to form a plate-typeheat exchanger.

FIG. 4 shows the gasket 3 illustrated in FIG. 3 mounted in the heatexchanger shown in FIG. 2. As will appear from the dash-dotted lines,part of the flaps 11 on the gasket 3 extend into the openings 8 on theplate 1. Preferably the flaps 11 snap into the openings 8, but theattachment can also be accomplished by a purely clamping effect whereinthe soft material of the gasket 3 thus merely squeezes around theopenings 8. As mentioned previously the openings 8 can feature burrs asa result of the cutting and ridging procedures. Following mounting ofthe gasket 3, such burrs can engage with the rubber material and thuscontribute to further securing the gasket 3.

FIG. 5 shows an alternative embodiment of a heat exchanger plate 21 inaccordance with the invention.

Again, the plate 21 is provided with a gasket groove 26 having anexpanded portion 27. In this embodiment the expanded portion 7 isprovided by ridging of material from the gasket groove 6 in such amanner that two identical, tongue-like portions 29 are formed, each ofwhich corresponds substantially to the tongue 9 in the embodiment shownin FIG. 2. The upper edges of both tongues 29 being free, they are notinfluenced by the remaining plate elements of the plate 21 and theircontractions, if any, during manufacture of the plate 21, with theresult that the mutual distances between the openings formed 28—of whichthere is a total of four, two for each tongue 29—are determinedaccurately within narrow limits.

The formation of two tongues 29 rather than one means that there aremore options with regard to the configuration of the associated gasket,of which three are shown in FIGS. 6–8.

FIG. 6 shows a gasket 33 provided with a coupling element 30 in the formof a centrally protruding coupling flap 31 and two external flaps 32.The central coupling flap 31 has a width that, in general, slightlyexceeds the distance between the two ridged tongues 29 in the expandedportion 27 of the plate 21, whereby it can be clamped tightly betweenthe openings 28 of the two tongues 29. The external flaps 32 areconfigured to be complementary with the outermost areas of the expandedportion 27 of the plate 21, whereby the gasket 33 fills the entireexpanded portion 27 when mounted. In this embodiment, the external flaps32 as such do not contribute to securing the gasket 33 in the gasketgroove 26 and, as it is, they might as well be omitted.

The mounting of the gasket 33 is accomplished by arranging same in thegasket groove 26 and pressing the central coupling flap 31 down betweenthe two tongues 29 whereby it snaps into the openings 28 of the tongues29 and is secured herein below the upper edges of the tongues 29.

In order to facilitate mounting the gasket 33 can, as shown in FIG. 7,be provided with a pressure element 34 arranged above the couplingelement 30 of the gasket 33 that has been shown in dashed lines. Thepressure element 34 is coherent with the central coupling flap 31 andthe external flaps 32 without, however, the functionality of the centralflap 31 being influenced. On its top face the pressure element 34 isprovided with a pressure cushion 35 in the form of an upwardly archedthickening. When the gasket 33 shown in FIG. 7 is mounted in the plate21, the coupling element 30 of the gasket 33 is pressed into theexpanded part 27 of the plate 21 by application of downwards pressureonto the pressure cushion 35. The configuration of the coupling element30 with a superjacent pressure element 34 is particularly interesting ifthe gasket 33 is to be mounted mechanically in the gasket groove 26, butit also presents certain advantages from a production point of view inconnection with the manufacture of the gasket 33.

FIG. 8 shows yet an alternative embodiment of a gasket that can bemounted in the plate 21 shown in FIG. 5.

Like the coupling element 30 on the gasket 33 shown in FIGS. 6 and 7,the coupling element 40 of this gasket 43 consists of a central flap 41and two external flaps 42. In this embodiment the external flaps 42 arethe ones that will, upon mounting on the heat exchanger plate 21, engagewith the openings 28 formed at the external sides of the ridged tongues29, each of these external flaps 42 being provided with an inwardlyprotruding portion. The configuration of the coupling element 40 of thegasket 43 thus corresponds, in principle, to the configuration of thecoupling element 10 of the gasket 3 (FIG. 2), there merely being alonger distance between the external flaps 42 than between theprotruding flaps 11.

The central flap 41 can be configured such that it fits tightly downbetween the ridged tongues 29 whereby it contributes to securing thegasket 43 when it is mounted on the plate 21. However, it may also havea width that is smaller than the distance between the ridged tongues 29which means that it does not contribute to securing the gasket 43, or itcan optionally be omitted altogether.

The invention has been described with reference to preferred embodimentsshown in the drawing, but alternative embodiments that are within thescope of the invention are perceivable, however. For instance thecoupling elements 10 and 40, respectively, of the gaskets (3) (FIG. 3)and 43 (FIG. 8) can be provided with a superjacent pressure elementcorresponding to the pressure element 34 shown in FIG. 7 to facilitatemounting on the heat exchanger plates 1 and 21, respectively.

The coupling elements 10, 30 and 40 of the gaskets are shown in theembodiments as protruding from the gaskets 3, 33 and 43 with rounded,soft contours that impart to the gasket certain advantageous featureswith regard to strength and production. However, nothing prevents thecoupling elements from being configured in other ways.

1. A heat exchanger plate for use in combination with a gasket in aplate-type heat exchanger, said plate comprising a gasket groove formedby an indentation that extends through at least portion of the heatexchanger plate spaced from the periphery of the plate, a plurality ofexpanded groove portions disposed in substantially the same plane assaid gasket groove at spaced intervals, a first ridged, tongue-likeportion disposed in each of the expanded groove portions extendingupwardly from the gasket groove, said first tongue-like portion formedby cutting and ridging of the heat exchanger plate to expose first andsecond openings on the respective sides of said first tongue-likeportion substantially perpendicular to the longitudinal direction of thegasket groove, said gasket including a plurality of coupling elements,each of said coupling elements configured to be received in a respectiveone of said expanded groove portions and engaged by said firsttongue-like portion.
 2. A heat exchanger plate according to claim 1,further comprising a second ridged, tongue-like portions disposed at adistance from said first tongue-like portion in each of the expandedgroove portions.
 3. A heat exchanger plate according to claim 1, whereinsaid first tongue-like portion is provided centrally in each of theexpanded portions; and wherein each of the coupling elements of thegasket comprises two protruding flaps configured for engagement withinthe first and second openings.
 4. A heat exchanger plate according toclaim 3, wherein the flaps on each of the coupling elements of thegasket extend partially into the first and second openings.
 5. A heatexchanger plate according to claim 3, wherein the flaps on each of thecoupling elements of the gasket extend marginally into the first andsecond openings.
 6. A heat exchanger plate according to claim 3, whereineach of the coupling elements of the gasket is provided with asuperjacent pressure element.
 7. A heat exchanger plate according toclaim 1, further comprising a second ridged, tongue-like portions spacedfrom said first tongue-like portion in each of the expanded grooveportions, said second ridged tongue-like portion formed by cutting andridging of the heat exchanger plate to expose third and fourth openingson the respective sides of said second tongue-like portion, said firstopening and said third opening defining proximal, mutually facingopenings; and wherein each of the coupling elements of the gasketcomprises a protruding flap configured for engagement within theproximal, mutually facing openings.
 8. A heat exchanger plate accordingto claim 7, wherein the flaps on the each of coupling elements of thegasket extend partially into the proximal, mutually facing openings. 9.A heat exchanger plate according to claim 7, wherein the flaps on eachof the coupling elements of the gasket extend marginally into theproximal, mutually facing openings.
 10. A heat exchanger plate accordingto claim 7, wherein the coupling element of the gasket is provided witha superjacent pressure element.
 11. A heat exchanger plate according toclaim 1, further comprising a second ridged, tongue-like portions spacedfrom said first tongue-like portion in each of the expanded grooveportions, said second ridged tongue-like portion formed by cutting andridging of the heat exchanger plate to expose third and fourth openingson the respective sides of said second tongue-like portion, said secondopenings and said fourth opening defining opposed, distal openings; andwherein each of the coupling elements of the gasket comprises twooutwardly protruding flaps that are configured for engagement within theopposed distal openings.
 12. A heat exchanger plate according to claim11, wherein the flaps on each of the coupling elements of the gasketextend partially into the opposed distal openings.
 13. A heat exchangerplate according to claim 11, wherein the flaps on each of the couplingelements of the gasket extend marginally into the opposed distalopenings.
 14. A heat exchanger plate according to claim 11, wherein eachof the coupling elements of the gasket is provided with a superjacentpressure element.
 15. A heat exchanger plate according to claim 1,wherein each of the coupling elements of the gasket is provided with asuperjacent pressure element.
 16. A heat exchanger plate for use incombination with a gasket in a plate-type heat exchanger, said platecomprising a gasket groove formed by an indentation that extends throughat least portion of the heat exchanger plate spaced from the peripheryof the plate, a plurality of expanded groove portions disposed insubstantially the same plane as said gasket groove at spaced intervals,a first ridged, tongue-like portion disposed in each of the expandedgroove portions extending upwardly from the gasket groove, said firsttongue-like portion formed by cutting and ridging of the heat exchangerplate to expose first and second openings on the respective sides ofsaid first tongue-like portion substantially perpendicular to thelongitudinal direction of the gasket groove, said gasket including aplurality of coupling elements, each of said coupling elementsconfigured to be received in a respective one of said expanded grooveportions and including protruding flaps that are engaged within saidfirst and second openings by said first tongue-like portion.
 17. A heatexchanger plate according to claim 16, wherein the flaps on the couplingelement of the gasket extend partially into the first and secondopenings.
 18. A heat exchanger plate according to claim 17, wherein eachof the coupling elements of the gasket is provided with a superjacentpressure element.
 19. A heat exchanger plate according to claim 16,wherein the flaps on each of the coupling elements of the gasket extendmarginally into the first and second openings.
 20. A heat exchangerplate according to claim 19, wherein each of the coupling elements ofthe gasket is provided with a superjacent pressure element.